Abstract: Chitin and chitosan are natural organic matters with rich resources and wide applications due to their various bioactivities.In this paper,research progresses on the hemostasis activities and action mechanisms of chitin,chitosan,and their derivatives at home and abroad are summarized.Some hemostasis dressings based on chitin or chitosan are introduced.In addition,the derivatives such as sulfated derivatives showed the anticoagulant activity which contrary to chitin and chitosan,so their recent research developments are also presented..